This thesis presents the first work, to our knowledge, to evaluate the potential of Optical Coherence Tomography (OCT) as an intravascular imaging modality to characterize and guide interventions on chronic total occlusions (CTOs) in arteries. An ex vivo imaging study using OCT is presented that characterizes various pathologies associated with peripheral CTOs and illustrates the ability to differentiate between the vessel wall and the occluded lumen. We also found that, while OCT could image approximately 1mm through tissue, it was effective for imaging deeper through clarified microchannels seen within the occluded lumen. While others had reported observing such microchannels within the lumen before, little was known about the global architecture of these channels. This motivated a study of the global morphology of microchannels in occlusions using micro computed tomography (microCT). In this microCT study, we found that microchannels within the occluded lumen of the artery appeared to be continuous over several millimeters. However, these channels also exited the artery frequently, suggesting the need for some form of imaging guidance. As a potential intravascular imaging set-up, a forward-viewing OCT catheter was built. This catheter uses a novel scanning mechanism that combines high voltage and a dissipative polymer to achieve fast compact actuation. Doppler OCT results are presented using this catheter to image flow in the forward direction. Doppler OCT imaging of microchannels in vivo is also shown in a surgically exposed occluded artery in situ.

This thesis presents the first work, to our knowledge, to evaluate the potential of Optical Coherence Tomography (OCT) as an intravascular imaging modality to characterize and guide interventions on chronic total occlusions (CTOs) in arteries. An ex vivo imaging study using OCT is presented that characterizes various pathologies associated with peripheral CTOs and illustrates the ability to differentiate between the vessel wall and the occluded lumen. We also found that, while OCT could image approximately 1mm through tissue, it was effective for imaging deeper through clarified microchannels seen within the occluded lumen. While others had reported observing such microchannels within the lumen before, little was known about the global architecture of these channels. This motivated a study of the global morphology of microchannels in occlusions using micro computed tomography (microCT). In this microCT study, we found that microchannels within the occluded lumen of the artery appeared to be continuous over several millimeters. However, these channels also exited the artery frequently, suggesting the need for some form of imaging guidance. As a potential intravascular imaging set-up, a forward-viewing OCT catheter was built. This catheter uses a novel scanning mechanism that combines high voltage and a dissipative polymer to achieve fast compact actuation. Doppler OCT results are presented using this catheter to image flow in the forward direction. Doppler OCT imaging of microchannels in vivo is also shown in a surgically exposed occluded artery in situ.

Thesis (M.S.)--University of Michigan, 1992.

Thesis (Ph. D.)--University of California, San Diego and San Diego State University, 2005. / Vita. Includes bibliographical references.

Thesis (M.S.)--University of Michigan, 1992.

Class of 2006 Abstract / Objectives: To determine the cost-effectiveness of urokinase (UK) and alteplase (recombinant tissue plasminogen activator, rt-PA) when used intra-arterially for the treatment of acute peripheral arterial occlusions. Methods: A decision analytic model was constructed using TreeAge Pro 2005 Suite to determine the cost- effectiveness of these therapies. Data for costs and probabilities were collected from published literature, as well as other references. Average and incremental cost-effectiveness ratios were calculated with a 95% confidence interval. A two-dimensional (sampling plus trials) Monte Carlo analysis with 5,000 patients was performed, along with a sensitivity analysis of the costs and variables. The costs measured were direct medical costs from the perspective of the healthcare institution. The primary outcome variable assessed in this model was 30-day survival. Results: The Monte Carlo microsimulation indicated that average cost-effectiveness (C/E) ratio for rt-PA was $54,141 (95th CI: 44,647 to 62,832) per successful treatment, while the average C/E ratio for UK was $65,515 (95th CI: 56,286 to 76,135). The ICER for rt-PA versus UK as the baseline was calculated to be $284,170 per additional survival over 30 days (95th CI: 186,097 to 418,443). Neither strategy was dominant. Conclusions: This study found rt-PA to be less costly but also slightly less efficacious than UK for patients treated for acute arterial occlusions. Neither therapy was indicated to be dominant over the other in terms of 30-day survival. Further long-term outcome data is necessary to more extensively assess the benefits of each therapy.

Os exercícios de trato vocal semiocluído (ETVSO) são técnicas vocais que têm como objetivo promover uma voz mais eficaz com o mínimo de esforço. ETVSO podem ser realizados utilizando tubos rígidos ou flexíveis imersos em água, os quais podem produzir resultados distintos e interferir na sua indicação em intervenções fonoaudiológicas. Este trabalho tem como objetivos: verificar os efeitos do exercício de fonação em diferentes tipos de tubos de ressonância em relação a aspectos vocais, laríngeos, respiratórios e de autopercepção; verificar se essas modificações ocorrem da mesma forma em indivíduos sem e com disfonia, em homens e mulheres e de diversas faixas etárias; verificar o comportamento laríngeo durante os exercícios. Para isso foram avaliados 75 indivíduos, entre 20 anos e 69 anos, sem ou com disfonias. Os participantes responderam questões sobre sintomas vocais e autopercepção do efeito do exercício, além de serem submetidos à avaliação perceptivoauditiva, acústica, respiratória e laríngea. O Índice de Concordância Kappa verificou a confiabilidade intra-avaliador nas análises perceptivas. Para comparação entre os momentos pré e pós imediatos à realização dos exercícios foram realizados Teste TStudent Pareado, Teste de Igualdade de Duas Proporções (p<0,05). Após o ETVSO com Lax Vox houve aumento de todos os parâmetros de instabilidade da frequência fundamental, principalmente para os indivíduos a partir de 50 anos e para as mulheres; aumentou o índice de fonação suave para todos os subgrupos, com exceção dos indivíduos a partir de 50 anos; aumentou o tempo máximo de fonação (TMF) de /z/ para diversos grupos, mas diminuiu o TMF do /a/ para mulheres; o volume fonatório reduziu para indivíduos a partir de 50 anos. Após o ETVSO com o tubo Finlandês, a voz se tornou mais grave, principalmente para homens, houve redução da variação de amplitude para todos os subgrupos, exceto a partir de 50 anos, aumento do TMF de /s/ e /z/, em especial para disfônicos. Com o tubo de Alta Resistência, os parâmetros de instabilidade da frequência fundamental aumentaram, principalmente para os indivíduos até 49 anos e para os não disfônicos; a variabilidade de amplitude diminuiu para indivíduos até 49 anos, não disfônicos e para mulheres; aumentou o índice de fonação suave para mulheres e aumentou TMF de z para participantes até 49 anos. Após os ETVSO com o canudo Padrão Refrigerante, os parâmetros de instabilidade de frequência aumentaram para disfônicos, mulheres, indivíduos até 49 anos; a perturbação de amplitude aumentou para mulheres; o índice de fonação suave aumentou para indivíduos a partir de 50 anos, não disfônicos e homens; aumentou TMF de /z/, principalmente para disfônicos. Considerando a somatória dos efeitos de todos os ETVSO, os disfônicos apresentaram melhora no fechamento glótico, assim como os homens. Os exercícios promoveram aumento da vibração da laringe e da mucosa, principalmente o LaxVox. Os tubos Finlandês e LaxVox foram percebidos como de efeitos mais positivos pelos participantes. Conclui-se que os efeitos dos ETVSO são distintos quando realizados com diferentes tipos de tubos e em diferentes populações, o que deve ser considerado em intervenções de reabilitação e aprimoramento vocais. / The semioccluded vocal tract exercises (SOVTE) are vocal techniques that aim to promote a more effective voice with minimal effort. SOVTE can be performed using rigid or flexible tubes immersed in water, which can produce distinct results and interfere in their indication in speech-language interventions. This study aims to: verify the effects of the phonation exercise in different types of resonance tubes in relation to vocal, laryngeal, respiratory and self-perception aspects; to verify if these modifications occur in the same way in individuals with and without dysphonia, in men and women and of diverse age groups; to verify the laryngeal behavior during the exercises. For that, 75 individuals, aged 20 years and 69 years, with or without dysphonias were tested. Participants answered questions about vocal symptoms and self-perception of the effect of the exercise, besides being submitted to auditive, acoustic, respiratory and laryngeal perceptual tests. The Kappa Concordance Index verified the intra-rater reliability in the perceptual analyzes. For the comparison between the immediate moments before and after the exercises were performed TStudent Test, Equality Test of Two Proportions (p <0.05). After the SOVTE with Lax Vox, there was an increase in all fundamental frequency instability parameters, mainly for individuals aged 50 and over, and for women; increased was the soft phonation index for all subgroups, with the exception of individuals aged 50 years and older; increased the maximum phonation time (MPT) of / z / for several groups, but decreased MPT of /a/ for women; the phonatory volume was reduced for individuals from 50 years of age. After the SOVTE with the Finnish tube, voice became deeper, especially for men, there was a reduction of the amplitude variation for all subgroups, except from 50 years, an increase in the MPT of / s / and / z /, in especially for dysphonics. With the High Resistance tube, fundamental frequency instability parameters increased, especially for individuals up to 49 years old and for nondysphonic individuals; the variability of amplitude decreased for individuals up to 49 years, non-dysphonic and for women; increased was the soft phonation index for women and increased MPT of / z / for participants up to 49 years old. After the SOVTE with the Standard Refrigerant straw, the parameters of frequency instability increased for dysphonics, women, individuals up to 49 years old; the amplitude disturbance increased for women; the soft phonation rate increased for individuals aged 50 years and older, non-dysphonic and men; increased MPT of / z /, especially for dysphonics. Considering the sum of the effects of all SOVTE, dysphonics presented improvement in glottic closure, as did men. The exercises promoted increased vibration of the larynx and mucosa, mainly LaxVox. The Finnish and LaxVox tubes were perceived as having more positive effects by the participants. It is concluded that the effects of SOVTE are different when performed with different types of tubes and in different populations, which should be considered in vocal rehabilitation and improvement interventions.

Nous présentons dans ce manuscrit les méthodes développées et les résultats obtenus dans notre travail de thèse sur l'analyse du contenu dynamique de scène visuelle. Nous avons considéré la configuration la plus fréquente de vision par ordinateur, à savoir caméra monoculaire et vidéos naturelles de scène extérieure. Nous nous concentrons sur des problèmes importants généraux pour la vision par ordinateur et d'un intérêt particulier pour l'industrie cinématographique, dans le cadre de la post-production vidéo. Les problèmes abordés peuvent être regroupés en deux catégories principales, en fonction d'une interaction ou non avec les utilisateurs : l'analyse interactive du contenu vidéo et l'analyse vidéo entièrement automatique. Cette division est un peu schématique, mais elle est en fait liée aux façons dont les méthodes proposées sont utilisées en post-production vidéo. Ces deux grandes approches correspondent aux deux parties principales qui forment ce manuscrit, qui sont ensuite subdivisées en chapitres présentant les différentes méthodes que nous avons proposées. Néanmoins, un fil conducteur fort relie toutes nos contributions. Il s'agit d'une analyse hiérarchique compositionnelle du mouvement dans les scènes dynamiques. Nous motivons et expliquons nos travaux selon l'organisation du manuscrit résumée ci-dessous. Nous partons de l'hypothèse fondamentale de la présence d'une structure hiérarchique de mouvement dans la scène observée, avec un objectif de compréhension de la scène dynamique. Cette hypothèse s'inspire d'un grand nombre de recherches scientifiques sur la vision biologique et cognitive. Plus précisément, nous nous référons à la recherche sur la vision biologique qui a établi la présence d'unités sensorielles liées au mouvement dans le cortex visuel. La découverte de ces unités cérébrales spécialisées a motivé les chercheurs en vision cognitive à étudier comment la locomotion des animaux (évitement des obstacles, planification des chemins, localisation automatique) et d'autres tâches de niveau supérieur sont directement influencées par les perceptions liées aux mouvements. Fait intéressant, les réponses perceptuelles qui se déroulent dans le cortex visuel sont activées non seulement par le mouvement lui-même, mais par des occlusions, des désocclusions, une composition des mouvements et des contours mobiles. En outre, la vision cognitive a relié la capacité du cerveau à appréhender la nature compositionnelle du mouvement dans l'information visuelle à une compréhension de la scène de haut niveau, comme la segmentation et la reconnaissance d'objets. / The manuscript that is presented here contains all the findings and conclusions of the carried research in dynamic visual scene analysis. To be precise, we consider the ubiquitous monocular camera computer vision set-up, and the natural unconstrained videos that can be produced by it. In particular, we focus on important problems that are of general interest for the computer vision literature, and of special interest for the film industry, in the context of the video post-production pipeline. The tackled problems can be grouped in two main categories, according to the whether they are driven user interaction or not : user-assisted video processing tools and unsupervised tools for video analysis. This division is rather synthetic but it is in fact related to the ways the proposed methods are used inside the video post-production pipeline. These groups correspond to the main parts that form this manuscript, which are subsequently formed by chapters that explain our proposed methods. However, a single thread ties together all of our findings. This is, a hierarchical analysis of motion composition in dynamic scenes. We explain our exact contributions, together with our main motivations, and results in the following sections. We depart from a hypothesis that links the ability to consider a hierarchical structure of scene motion, with a deeper level of dynamic scene understanding. This hypothesis is inspired by plethora of scientific research in biological and psychological vision. More specifically, we refer to the biological vision research that established the presence of motion-related sensory units in the visual cortex. The discovery of these specialized brain units motivated psychological vision researchers to investigate how animal locomotion (obstacle avoidance, path planning, self-localization) and other higher-level tasks are directly influenced by motion-related percepts. Interestingly, the perceptual responses that take place in the visual cortex are activated not only by motion itself, but by occlusions, dis-occlusions, motion composition, and moving edges. Furthermore, psychological vision have linked the brain's ability to understand motion composition from visual information to high level scene understanding like object segmentation and recognition.

Neurologinių sutrikimų nustatymui dažnai naudojamas sekamųjų akių judesių tyrimas. Tačiau mokslinėje literatūroje nėra detaliai išnagrinėtas vienas sekamųjų akių judesių parametras – pasivejančių sakadų tarpsakadinis laiko intervalas. Taip pat, pasivejančių sakadų parametrų priklausomybė nuo sekamo objekto trajektorijos ir greičio nėra aiški. Šio darbo tikslas - ištirti sekimo paklaidos, sakadų dažnio aplink okliuzijas ir tarpsakadinių laiko intervalų priklausomybę nuo sekamo objekto trajektorijos tipo ir jo judėjimo greičio. / Human oculomotor system analysis is often used to diagnose neurological disorders by studying tracking eye movements of the patient. However, one of the parameters of tracking eye movements is not thoroughly investigated – the intersaccadic interval of catch up saccades. Also, dependencies of parameters of catch-up saccades on different target trajectories and velocities are not clear. The aim of this paper is to study the dependency of tracking error, frequency distribution around occlusions and intersaccadic interval of catch-up saccades on target trajectory and velocity.

京都大学 / 0048 / 新制・課程博士 / 博士(情報学) / 甲第19342号 / 情博第594号 / 新制||情||103(附属図書館) / 32344 / 京都大学大学院情報学研究科システム科学専攻 / (主査)教授 石井 信, 教授 杉江 俊治, 教授 大塚 敏之 / 学位規則第4条第1項該当 / Doctor of Informatics / Kyoto University / DFAM